                        <table class="table table-hover table-bordered" style="width:86%;margin:auto;">
                            {x2;if:$sections}
                            {x2;tree:$sections,section,sid}
                            <tr class="info">
                                <td colspan="3">{x2;v:section['section']}</td>
                            </tr>
                            <tr>
                                {x2;tree:$knows[v:section['sectionid']],know,kid}
                                <td><input type="checkbox" value="{x2;v:know['knowsid']}"/> {x2;v:know['knows']}</td>
                                {x2;if:v:kid % 3 == 0}
                                </tr><tr>
                                {x2;endif}
                                {x2;endtree}
                            </tr>
                            {x2;endtree}
                            {x2;else}
                            <tr class="info">
                                <td colspan="3">请先选择科目</td>
                            </tr>
                            {x2;endif}
                        </table>
